It is often a problem to clean and/or repaint large items (“work pieces”) such as locomotive engines and airplanes. Such operations usually involve sand blasting, spraying paint and solvents over an item, device, or piece of equipment having a large surface, thereby depositing solid waste over a large area of the building that houses the work piece and also expelling airborne contaminants into the atmosphere. The amount of solid waste generated can render the spraying area unusable for a long period of time, if not permanently. Regarding airborne waste, it is well known that unpermitted delivery of airborne contaminants into the atmosphere fouls the air and is against the law.
Often this problem is addressed by transporting the work piece to a permanent cleaning/painting facility equipped to clean and/or paint the work piece and to handle the waste generated when it is serviced. However, this puts the work piece out of commission not only for the cleaning period but also for the transport period. This can lead to additional expense over and above the actual cost of cleaning or painting as transport of such items is expensive and may require the purchase of backup equipment to maintain operations. It would be advantageous to provide the equipment and processes needed for the service and maintenance of work pieces, especially large work pieces, without moving them from their principal or operational locations to reduce both the cost and the downtime generated during the cleaning/painting operation.
There have been previous attempts to solve this problem. U.S. Pat. No. 7,156,889 to Swanson, et al. discloses a mobile assembly for removing dust from a gas stream. The entire assembly is mounted on a trailer, such as a semi trailer, and includes an extendable/retractable portion that incorporates a flexible air tunnel with collapsible dust bags at one end. The assembly also includes ventilation fans. The primary gas intake extends transversely from between a two part filter system so that when entering the filters the air or gas flow is divided and must turn perpendicularly to the path of air entering the intake. Moreover, the Swanson patent is used to remove dust from industrial collectors and is designed to clean large items left in place in their primary locations.
U.S. Pat. No. 6,402,613 to Teagle is a portable environmental control system used to evacuate gases from an interior space in a building. The unit is placed in an adjoining room with a blower unit positioned between a flexible intake duct and a flexible outlet duct that is directed to a filter unit or the outside air. The intake duct is fitted into an opening to the target room and contaminated air is removed to the filter or outside through the blower. The filter system of the Teagle device as well as the position of the blower in relation to the filter does not enable it to be used to evacuate large volume structures such as plane hangers, locomotive maintenance sheds, and similar large enclosures.
U.S. Pat. No. 4,909,815 discloses a mobile air cleaning apparatus for use within auto body shops. It possesses a C shape with a base having an air intake, an upright column with filters and a fan, and an overhanging hood which expels filtered air. The apparatus is designed to be placed over a relatively small area, in which air contaminants are generated, such as a car hood being sanded or painted. The filtered air is recirculated over the target area to take up additional contaminants to be carried to the filters. However, the apparatus is limited to recirculating air and does not remove contaminants from the work area or building housing the work area.
U.S. Pat. No. 4,323,377 to Jolin discloses a mobile dust collector that utilizes a series of filter cartridges that lead to a conical dust hopper. Although the device is mounted on a trailer frame, the entire unit must be rotated to a vertical position to enable the dust hopper to catch dust dropping from the filters. An intake duct is connected to the unit and air is forced over the filters which catch the dust on the outside of the filter while filtered air is expelled though the filter to the environment. The Jolin dust collector does not allow for large intake systems that allow for removal of contaminants from large buildings.
U.S. Pat. No. 6,569,217 to DeMarco is a mobile dust collector that utilizes a cyclone separator to separate large and small dust particles. The finer dust particles are filtered and collected in one or more dust bins. Similar to the Jolin apparatus discussed above, the DeMarco dust collector lacks the ability to be adapted to seal doors and similar sized openings to remove contaminants directly from enclosures.
U.S. Pat. No. 5,090,972 to Eller, et al. discloses an environmental control system used to remove hazardous materials from a work area. However, the disclosed system is not mobile and requires different configurations of inlet and outlet ducts for each job site.
Thus, there is a need in the field for a mobile device or system that is self contained and able to move large volumes of air through structures housing large work pieces with the aim of generating an air flow around the work piece to carry contaminated air to the mobile filtering system.